Commonly used water is a mixture of H2O (light water); and D2O (heavy water) and DHO (semi-heavy water) which are water molecules containing a deuterium atom, an isotope of a hydrogen atom. A concentration of heavy water and semi-heavy water contained in water of nature differs depending on places to be collected, but in level grounds, the concentration is about 150 ppm, most of which are semi-heavy water.
A quantity of heavy water and semi-heavy water in an adult weighing 60 kg is, for example, as minute as 95 ppm.
However, heavy water and semi-heavy water are different from light water in physical properties such as solubility, electrical conductivity, and ionization degree of substances as well as a reaction speed of the substances. Therefore, high intake of heavy water or semi-heavy water causes malfunctions in biological reactions, and pure heavy water annihilates living organisms. Accordingly, it is said that a lower deuterium concentration in drinking water and the like is preferable for human health, which is now being studied.
Deuterium depleted water containing almost no heavy water or semi-heavy water is not approved by the Japanese Ministry of Health, Labor and Welfare, but is approved in Hungary as an anticancer drug for animals, and is taken by many cancer patients and the like.
To produce deuterium depleted water from commonly used water, the following techniques have been known in the related art, that is, repeated distillation utilizing a slight difference in physical property between hydrogen and deuterium (Patent Literature 1), and a water electrolysis method (Patent Literature 2).
However, the conventional methods for producing deuterium depleted water require large-scale equipment, and repetition of complicated operations, which leads to high manufacturing costs. Such reasons impose large economic burdens on cancer patients and those who take deuterium depleted water in anticipation of various efficacy.